Numerous items are available on the market that require inflation with a gas to moderate pressures (often air) The situation often require that many of these items must be filled so that the overall time required to fill them requires a substantial period of time.
Examples of such items include balloons, balls, and cushions, for stadium seats. The numbers of items to be filled can be hundreds or even thousands. The time required to fill these items becomes an important cost factor.
An important application of an air filled cushion in industry is the dunnage bags such as are used to cushion freight during transit.
These bags are typically about four to eight feet on a side and are ten to twenty inches thick. They are positioned between stacks of cargo, typically on pallets and carried on trucks, planes, or ships.
The demand for “streamlining” the dunnage bag industry has resulted in significant economizing and reliability not only in the construction of the bag but also in the tools and method for filling and emptying the bag.
A typical “dunnage bag”, is an inflatable bag made of paper and/or other synthetic material with an airtight liner. The bag is placed on a conveying vehicle between stacks of cargo to prevent the shifting of cargo during transportation. Each bag is placed in the space between the cargo and the walls of the container or between neighboring rows of pallets holding cargo and then inflated. The bags are typically inflated to a pressure of not more than 1½ to 2 pounds per square inch (psi). In some operations, the time required to empty the bags is so expensive that, when the cargo arrives at its destination and prior to unloading, the bags are simply punctured and discarded. Destroying the bag avoids spending the time to empty air out of the bag after the destination is reached.
The remaining problem is to reduce the time required to inflate the bag in preparation for its journey.
In response to the demand for an improved dunnage bag system including shortening the operation time, a number of concepts have been disclosed.
U.S. Pat. No. 5,042,663 to Heinrick discloses joinable inflatable bladders for packaging.
U.S. Pat. No. 5,431,525 to Sansone et al discloses a dual air bladder air bag.
Other approaches to economizing the dunnage bag system have included improved valves.
For example, U.S. Pat. No. 4,073,389 to Angarola et al discloses a housing engaging a spring loaded plug that permits one way entry of air into the bag. However, the valve tends to dysfunction and leak with aging of the spring.
U.S. Pat. No. 4,102,364 to Leslie et al discloses a system for rapid pressurizing the air inside the bag from a source of high pressure air.
U.S. Pat. Nos. 4,146,069 and 4,146,070 to Angarola et al discloses another system for rapid filling using a stream of pressurized air to aspirate ambient air into the bag.
U.S. Pat. No. 5,111,838 to Langston discloses a spring loaded valve member movable to open a passage and threaded opening to engage an air hose.
U.S. Pat. No. 5,806,572 discloses an apparatus for inflating a bag to a desired limit.
U.S. Pat. No. 6,053,222 discloses a gun that both inflates the bag when required and accelerates deflation of the bag when required.
None of the several versions of a valve for a dunnage bag described in the cited art address the problem of how to reduce the time required to inflate the bag. Typical inflation systems are characterized by a constant high pressure so that air initially flows into the bag at a fast rate but flow slows down as the target pressure is reached.